An experimental M2DFE detector

A 53.33 Mb/s experimental extended multi-level decision feedback equalizati on (M2DFE) read channel has been designed and implemented using discrete-co mponents. The forward equalizer is the same as that of MDFE, consisting of two analog Bi-quads. The core of the detector contains two analog critical loops named as top and bottom MDFE loops and two digital error computation blocks (DEC) that compute, square, accumulate, and compare errors of the tw o MDFE loops when M2DFE is in erasure modes. The bench test confirms that M 2DFE has 1 dB gain in signal-to-noise ratio (SNR) and about 30% reduction i n error propagation over MDFE under the same test conditions. The experimen t also shows M2DFE performance is relatively robust against the variations of the parameter settings such as the values of inner and outer levels, and the threshold of the slicers of the two MDFE loops.